6 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 



cially soldiers an intimate knowledge of the physiology of walking is 

 obviously of great importance. 



Practically all of the previous researches on the physiology of walking 

 have been conducted either from a desire to study the conditions inci- 

 dental to walking done in mountain climbing, the results being of 

 importance to physicians and those taking regular exercise, or, as in the 

 case of the classical researches of Zuntz and Schumburg, from a desire 

 to study the influence of walking on the metabolism, with a view to 

 applying the results directly to army movements. In the present day, 

 when special attention is directed towards efficiency, the minimizing 

 of extraneous muscular movements, and the transportation of material 

 by hand and leg motion with the least possible expenditure of physical 

 energy, we may assume that there is every incentive for studying care- 

 fully the physiology incidental to walking in a horizontal direction. 



While from the abstract physiological standpoint a study of all of 

 the various factors incidental to walking is of great value, perhaps the 

 most important phase of the investigation is the study of the energy 

 transformations and the determination of the amount of nutrients in 

 the food necessary to provide for such activity. The results of such 

 study are of especial practical value in determining the energy require- 

 ments of an army engaged in marching a certain distance over a level 

 country. As previously stated, this thought dominated the study 

 of Zuntz and Schumburg. A more universal application of the results 

 may be made by the physician who, if he knows the energy involved in 

 walking, is able to prescribe more intelligently a definite amount of 

 exercise for the ambulatory patient. Furthermore, as physical exercise, 

 particularly walking, is an important factor in weight reduction and 

 in athletic training, exact information as to the energy required may 

 be put to practical use in such connection. 



Theoretically the movement of 1 kilogram 1 meter would call for no 

 positive work other than that in overcoming the resistance of the air; 

 nevertheless a considerable amount of work is required of the human 

 body as a machine in accomplishing this feat of moving the mass in a 

 horizontal direction. The apportionment of the total energy output 

 of the body between that required for the maintenance of the vital 

 functions and that required for walking is not, however, simple. When 

 a person is walking, not only is energy required for the external mus- 

 cular exercise, but a heat production is necessary for the entire main- 

 tenance of the body activities, including muscular tonus, the work of 

 circulation, respiratory muscles, and the external work of balancing the 

 body in an upright position, none of these activities contributing 

 directly to the work required to move the body in a horizontal direction. 

 With only a knowledge of the amount of food eaten, it is impossible to 

 estimate the proportion of food required for the activity of walking and 

 that for vital maintenance. A closer analysis is therefore essential. 



